The neem tree (Azadirachta indica or Melia azadirachta) found throughout India and other countries has been reported to have various medicinal utilities. In particular, various parts of the tree have been utilized in the treatment of arthritis (Pillal and Santhakumari 1981), inflammation (Okpanyi and Ezeukwu 1981) and malaria (Obbaseki and Jeged-Fadunsin, 1986). Neem oil, also known as oil of Margosa, has been shown to possess anti-diabetic (Chakrabarty and Poddar, 1984) anti-bacterial (Singh and Sastry, 1981), anti-fungal (Kher and Chaurasia, 1977) and anti-fertility effects in the female (Talwar, U.S. Pat. No. 5,196,197) .
The realization of the anti-fertility effects of neem oil in the female animal was quite important especially in view of the problems with population control in most developing countries. Alternative forms of birth control are also desirable in industrialized countries due to the recognized problems associated with known contraceptives. However, most contraceptives are aimed at controlling fertility in the female which unfairly imposes sole responsibility for birth control on the female. One accepted method of contraception in the male has been a vasectomy. However, this procedure has been reported to give rise to problems related to the formation of anti-sperm antibodies and associated changes in the epididymis and testes. (Herr, et al 1987; Flicklnger et al 1990). Consequently, there is a real need to provide new methods for blocking fertility in the male.